Still photography camera lenses come in many sizes, shapes and forms, but the one thing they all have in common, they collect the light that enters their barrel. Those rays of light pass through the optical elements of the lens, or aperture, similar to the pupil of the eye. It’s this aperture, or full opening of the lens, that determines the “cone angle” of these bundled rays, or “pencils of light,” that eventually strikes the imaging sensor in your digital camera providing you image sharpness and bokeh (the aesthetic quality of the blur). Some say, “It’s the bokeh that sets the photographic style of a photographer,” though in reality, it’s the lens construction that beckons bokeh...read more: http://www.lensdiaries.com/97s